style: add Styles._get_style_id_from_style()

Steve Canny · Steve Canny · commit ef5f1640b671 · 2015-02-08T00:01:15.000-08:00
diff --git a/docx/styles/styles.py b/docx/styles/styles.py
@@ -99,7 +99,14 @@ def _get_style_id_from_style(self, style, style_type):
         Return the id of *style*, or |None| if it is the default style of
         *style_type*. Raises |ValueError| if style is not of *style_type*.
         """
-        raise NotImplementedError
+        if style.type != style_type:
+            raise ValueError(
+                "assigned style is type %s, need type %s" %
+                (style.type, style_type)
+            )
+        if style == self.default(style_type):
+            return None
+        return style.style_id
 
     @staticmethod
     def _translate_special_case_names(name):
diff --git a/features/par-style-prop.feature b/features/par-style-prop.feature
@@ -16,7 +16,6 @@ Feature: Each paragraph has a read/write style
       | Body Text    | Body Text      |
 
 
-  @wip
   Scenario Outline: Set the style of a paragraph
      Given a paragraph
       When I assign a <style-spec> to paragraph.style
diff --git a/tests/styles/test_styles.py b/tests/styles/test_styles.py
@@ -100,6 +100,19 @@ def it_gets_a_style_id_from_a_name_to_help(self, id_name_fixture):
         )
         assert style_id is style_id_
 
+    def it_gets_a_style_id_from_a_style_to_help(self, id_style_fixture):
+        styles, style_, style_type, style_id_ = id_style_fixture
+
+        style_id = styles._get_style_id_from_style(style_, style_type)
+
+        styles.default.assert_called_once_with(style_type)
+        assert style_id is style_id_
+
+    def it_raises_on_style_type_mismatch(self, id_style_raises_fixture):
+        styles, style_, style_type = id_style_raises_fixture
+        with pytest.raises(ValueError):
+            styles._get_style_id_from_style(style_, style_type)
+
     # fixture --------------------------------------------------------
 
     @pytest.fixture(params=[
@@ -220,6 +233,23 @@ def id_name_fixture(self, _getitem_, _get_style_id_from_style_, style_):
         _get_style_id_from_style_.return_value = style_id_
         return styles, style_name, style_type, style_, style_id_
 
+    @pytest.fixture(params=[True, False])
+    def id_style_fixture(self, request, default_, style_):
+        style_is_default = request.param
+        styles = Styles(None)
+        style_id, style_type = 'FooBar', 1
+        default_.return_value = style_ if style_is_default else None
+        style_.style_id, style_.type = style_id, style_type
+        expected_value = None if style_is_default else style_id
+        return styles, style_, style_type, expected_value
+
+    @pytest.fixture
+    def id_style_raises_fixture(self, style_):
+        styles = Styles(None)
+        style_.type = 1
+        style_type = 2
+        return styles, style_, style_type
+
     @pytest.fixture(params=[
         ('w:styles',                           0),
         ('w:styles/w:style',                   1),
